1. Field of the Invention
The present invention relates to an actinic-ray- or radiation-sensitive resin composition that when exposed to actinic rays or radiation, reacts to thereby change its properties, and relates to an actinic-ray- or radiation-sensitive film formed from the composition and a method of forming a pattern with the use of the composition. More particularly, the present invention relates to an actinic-ray- or radiation-sensitive resin composition appropriately used in a semiconductor production process for an IC or the like, a circuit board production process for a liquid crystal, a thermal head or the like, other photofabrication processes, a lithographic printing plate and an acid-hardenable composition, and further relates to an actinic-ray- or radiation-sensitive film formed from the composition and a method of forming a pattern with the use of the composition.
2. Description of the Related Art
Heretofore, the microfabrication by lithography using a photoresist composition is performed in the process for manufacturing semiconductor devices, such as an IC and an LSI. In recent years, the formation of an ultrafine pattern in the submicron region or quarter-micron region is increasingly required in accordance with the realization of high integration for integrated circuits. Accordingly, the trend of exposure wavelength toward a short wavelength, for example, from g-rays to i-rays and further to a KrF excimer laser light is seen. To now, an exposure equipment using an ArF excimer laser of 193 nm wavelength as a light source has been developed. Further, the development of a method, known as a liquid-immersion method, in which the space between a projector lens and a sample is filled with a liquid of high refractive index (hereinafter also referred to as an “immersion liquid”) has progressed as a technology for enhancing the resolving power. Still further, the development of lithography using electron beams, X-rays, EUV light or the like, aside from the excimer laser light, is now being promoted. Accordingly, chemically amplified resist compositions that effectively respond to various types of radiations and excel in sensitivity and resolution are now being developed, and various compounds are being developed as acid generators being a major constituent thereof.
For example, acid generators capable of generating a perfluorinated alkanesulfonic acid can exhibit a satisfactory acid strength in the reaction of deprotection of a protective group whose deprotection is difficult, so that many thereof are brought into practical use. Further, various compounds having a fluorine content reduced relative to those of such conventional acid generators are proposed.
For example, patent reference 1 points out the problem that acid generators having a high fluorine content, such as a perfluoroalkylsulfonic acid, exhibit an extremely high acid strength, so that, in the leaving reaction of protective group capable of changing a dissolution contrast of resin, unanticipated reactions may occur to result in the occurrence of foreign matter either after the alkali development or at the detachment of the resist. Then, the reference discloses specified fluorinated sulfonic acid salts having a fluorine content reduced for solving the problem.
Further, patent reference 2 discloses specified fluorinated sulfonic acid salts that while reducing the fluorine content thereof to decrease environmental burdens, can exhibit satisfactory acidities as acid generators.
Still further, patent reference 3 discloses specified fluorinated sulfonic acid salts intended to increase the solubility of an alkanesulfonic acid salt having a reduced fluorine content in resist solvents to thereby enhance the resist performance, such as resolution.